2 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
3 * 2000 Wim Taymans <wim.taymans@chello.be>
4 * 2005 Wim Taymans <wim@fluendo.com>
6 * gstevent.c: GstEvent subsystem
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Library General Public
10 * License as published by the Free Software Foundation; either
11 * version 2 of the License, or (at your option) any later version.
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Library General Public License for more details.
18 * You should have received a copy of the GNU Library General Public
19 * License along with this library; if not, write to the
20 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
21 * Boston, MA 02110-1301, USA.
27 * @short_description: Structure describing events that are passed up and down
29 * @see_also: #GstPad, #GstElement
31 * The event class provides factory methods to construct events for sending
32 * and functions to query (parse) received events.
34 * Events are usually created with gst_event_new_*() which takes event-type
35 * specific parameters as arguments.
36 * To send an event application will usually use gst_element_send_event() and
37 * elements will use gst_pad_send_event() or gst_pad_push_event().
38 * The event should be unreffed with gst_event_unref() if it has not been sent.
40 * Events that have been received can be parsed with their respective
41 * gst_event_parse_*() functions. It is valid to pass %NULL for unwanted details.
43 * Events are passed between elements in parallel to the data stream. Some events
44 * are serialized with buffers, others are not. Some events only travel downstream,
45 * others only upstream. Some events can travel both upstream and downstream.
47 * The events are used to signal special conditions in the datastream such as
48 * EOS (end of stream) or the start of a new stream-segment.
49 * Events are also used to flush the pipeline of any pending data.
51 * Most of the event API is used inside plugins. Applications usually only
52 * construct and use seek events.
53 * To do that gst_event_new_seek() is used to create a seek event. It takes
54 * the needed parameters to specify seeking time and mode.
55 * |[<!-- language="C" -->
59 * // construct a seek event to play the media from second 2 to 5, flush
60 * // the pipeline to decrease latency.
61 * event = gst_event_new_seek (1.0,
63 * GST_SEEK_FLAG_FLUSH,
64 * GST_SEEK_TYPE_SET, 2 * GST_SECOND,
65 * GST_SEEK_TYPE_SET, 5 * GST_SECOND);
67 * result = gst_element_send_event (pipeline, event);
69 * g_warning ("seek failed");
75 #include "gst_private.h"
76 #include <string.h> /* memcpy */
80 #include "gstenumtypes.h"
85 GType _gst_event_type = 0;
91 GstStructure *structure;
92 gint64 running_time_offset;
95 #define GST_EVENT_STRUCTURE(e) (((GstEventImpl *)(e))->structure)
104 static GstEventQuarks event_quarks[] = {
105 {GST_EVENT_UNKNOWN, "unknown", 0},
106 {GST_EVENT_FLUSH_START, "flush-start", 0},
107 {GST_EVENT_FLUSH_STOP, "flush-stop", 0},
108 {GST_EVENT_SELECT_STREAMS, "select-streams", 0},
109 {GST_EVENT_STREAM_START, "stream-start", 0},
110 {GST_EVENT_STREAM_COLLECTION, "stream-collection", 0},
111 {GST_EVENT_CAPS, "caps", 0},
112 {GST_EVENT_SEGMENT, "segment", 0},
113 {GST_EVENT_TAG, "tag", 0},
114 {GST_EVENT_TOC, "toc", 0},
115 {GST_EVENT_PROTECTION, "protection", 0},
116 {GST_EVENT_BUFFERSIZE, "buffersize", 0},
117 {GST_EVENT_SINK_MESSAGE, "sink-message", 0},
118 {GST_EVENT_EOS, "eos", 0},
119 {GST_EVENT_SEGMENT_DONE, "segment-done", 0},
120 {GST_EVENT_GAP, "gap", 0},
121 {GST_EVENT_QOS, "qos", 0},
122 {GST_EVENT_SEEK, "seek", 0},
123 {GST_EVENT_NAVIGATION, "navigation", 0},
124 {GST_EVENT_LATENCY, "latency", 0},
125 {GST_EVENT_STEP, "step", 0},
126 {GST_EVENT_RECONFIGURE, "reconfigure", 0},
127 {GST_EVENT_TOC_SELECT, "toc-select", 0},
128 {GST_EVENT_CUSTOM_UPSTREAM, "custom-upstream", 0},
129 {GST_EVENT_CUSTOM_DOWNSTREAM, "custom-downstream", 0},
130 {GST_EVENT_CUSTOM_DOWNSTREAM_OOB, "custom-downstream-oob", 0},
131 {GST_EVENT_CUSTOM_DOWNSTREAM_STICKY, "custom-downstream-sticky", 0},
132 {GST_EVENT_CUSTOM_BOTH, "custom-both", 0},
133 {GST_EVENT_CUSTOM_BOTH_OOB, "custom-both-oob", 0},
134 {GST_EVENT_STREAM_GROUP_DONE, "stream-group-done", 0},
139 GST_DEFINE_MINI_OBJECT_TYPE (GstEvent, gst_event);
142 _priv_gst_event_initialize (void)
146 _gst_event_type = gst_event_get_type ();
148 g_type_class_ref (gst_seek_flags_get_type ());
149 g_type_class_ref (gst_seek_type_get_type ());
151 for (i = 0; event_quarks[i].name; i++) {
152 event_quarks[i].quark = g_quark_from_static_string (event_quarks[i].name);
157 * gst_event_type_get_name:
158 * @type: the event type
160 * Get a printable name for the given event type. Do not modify or free.
162 * Returns: a reference to the static name of the event.
165 gst_event_type_get_name (GstEventType type)
169 for (i = 0; event_quarks[i].name; i++) {
170 if (type == event_quarks[i].type)
171 return event_quarks[i].name;
177 * gst_event_type_to_quark:
178 * @type: the event type
180 * Get the unique quark for the given event type.
182 * Returns: the quark associated with the event type
185 gst_event_type_to_quark (GstEventType type)
189 for (i = 0; event_quarks[i].name; i++) {
190 if (type == event_quarks[i].type)
191 return event_quarks[i].quark;
197 * gst_event_type_get_flags:
198 * @type: a #GstEventType
200 * Gets the #GstEventTypeFlags associated with @type.
202 * Returns: a #GstEventTypeFlags.
205 gst_event_type_get_flags (GstEventType type)
207 GstEventTypeFlags ret;
209 ret = type & ((1 << GST_EVENT_NUM_SHIFT) - 1);
215 _gst_event_free (GstEvent * event)
219 g_return_if_fail (event != NULL);
220 g_return_if_fail (GST_IS_EVENT (event));
222 GST_CAT_LOG (GST_CAT_EVENT, "freeing event %p type %s", event,
223 GST_EVENT_TYPE_NAME (event));
225 s = GST_EVENT_STRUCTURE (event);
228 gst_structure_set_parent_refcount (s, NULL);
229 gst_structure_free (s);
232 g_slice_free1 (sizeof (GstEventImpl), event);
235 static void gst_event_init (GstEventImpl * event, GstEventType type);
238 _gst_event_copy (GstEvent * event)
243 copy = g_slice_new0 (GstEventImpl);
245 gst_event_init (copy, GST_EVENT_TYPE (event));
247 GST_EVENT_TIMESTAMP (copy) = GST_EVENT_TIMESTAMP (event);
248 GST_EVENT_SEQNUM (copy) = GST_EVENT_SEQNUM (event);
250 s = GST_EVENT_STRUCTURE (event);
252 GST_EVENT_STRUCTURE (copy) = gst_structure_copy (s);
253 gst_structure_set_parent_refcount (GST_EVENT_STRUCTURE (copy),
254 ©->event.mini_object.refcount);
256 GST_EVENT_STRUCTURE (copy) = NULL;
259 ((GstEventImpl *) copy)->running_time_offset =
260 ((GstEventImpl *) event)->running_time_offset;
262 return GST_EVENT_CAST (copy);
266 gst_event_init (GstEventImpl * event, GstEventType type)
268 gst_mini_object_init (GST_MINI_OBJECT_CAST (event), 0, _gst_event_type,
269 (GstMiniObjectCopyFunction) _gst_event_copy, NULL,
270 (GstMiniObjectFreeFunction) _gst_event_free);
272 GST_EVENT_TYPE (event) = type;
273 GST_EVENT_TIMESTAMP (event) = GST_CLOCK_TIME_NONE;
274 GST_EVENT_SEQNUM (event) = gst_util_seqnum_next ();
275 event->running_time_offset = 0;
280 * gst_event_new_custom:
281 * @type: The type of the new event
282 * @structure: (transfer full): the structure for the event. The event will
283 * take ownership of the structure.
285 * Create a new custom-typed event. This can be used for anything not
286 * handled by other event-specific functions to pass an event to another
289 * Make sure to allocate an event type with the #GST_EVENT_MAKE_TYPE macro,
290 * assigning a free number and filling in the correct direction and
291 * serialization flags.
293 * New custom events can also be created by subclassing the event type if
296 * Returns: (transfer full) (nullable): the new custom event.
299 gst_event_new_custom (GstEventType type, GstStructure * structure)
303 event = g_slice_new0 (GstEventImpl);
305 GST_CAT_DEBUG (GST_CAT_EVENT, "creating new event %p %s %d", event,
306 gst_event_type_get_name (type), type);
309 /* structure must not have a parent */
310 if (!gst_structure_set_parent_refcount (structure,
311 &event->event.mini_object.refcount))
315 gst_event_init (event, type);
317 GST_EVENT_STRUCTURE (event) = structure;
319 return GST_EVENT_CAST (event);
324 g_slice_free1 (sizeof (GstEventImpl), event);
325 g_warning ("structure is already owned by another object");
331 * gst_event_get_structure:
332 * @event: The #GstEvent.
334 * Access the structure of the event.
336 * Returns: (transfer none) (nullable): The structure of the event. The
337 * structure is still owned by the event, which means that you should not free
338 * it and that the pointer becomes invalid when you free the event.
343 gst_event_get_structure (GstEvent * event)
345 g_return_val_if_fail (GST_IS_EVENT (event), NULL);
347 return GST_EVENT_STRUCTURE (event);
351 * gst_event_writable_structure:
352 * @event: The #GstEvent.
354 * Get a writable version of the structure.
356 * Returns: (transfer none): The structure of the event. The structure
357 * is still owned by the event, which means that you should not free
358 * it and that the pointer becomes invalid when you free the event.
359 * This function checks if @event is writable and will never return
365 gst_event_writable_structure (GstEvent * event)
367 GstStructure *structure;
369 g_return_val_if_fail (GST_IS_EVENT (event), NULL);
370 g_return_val_if_fail (gst_event_is_writable (event), NULL);
372 structure = GST_EVENT_STRUCTURE (event);
374 if (structure == NULL) {
376 gst_structure_new_id_empty (gst_event_type_to_quark (GST_EVENT_TYPE
378 gst_structure_set_parent_refcount (structure, &event->mini_object.refcount);
379 GST_EVENT_STRUCTURE (event) = structure;
385 * gst_event_has_name:
386 * @event: The #GstEvent.
387 * @name: name to check
389 * Checks if @event has the given @name. This function is usually used to
390 * check the name of a custom event.
392 * Returns: %TRUE if @name matches the name of the event structure.
395 gst_event_has_name (GstEvent * event, const gchar * name)
397 g_return_val_if_fail (GST_IS_EVENT (event), FALSE);
399 if (GST_EVENT_STRUCTURE (event) == NULL)
402 return gst_structure_has_name (GST_EVENT_STRUCTURE (event), name);
406 * gst_event_get_seqnum:
407 * @event: A #GstEvent.
409 * Retrieve the sequence number of a event.
411 * Events have ever-incrementing sequence numbers, which may also be set
412 * explicitly via gst_event_set_seqnum(). Sequence numbers are typically used to
413 * indicate that a event corresponds to some other set of events or messages,
414 * for example an EOS event corresponding to a SEEK event. It is considered good
415 * practice to make this correspondence when possible, though it is not
418 * Note that events and messages share the same sequence number incrementor;
419 * two events or messages will never have the same sequence number unless
420 * that correspondence was made explicitly.
422 * Returns: The event's sequence number.
427 gst_event_get_seqnum (GstEvent * event)
429 g_return_val_if_fail (GST_IS_EVENT (event), -1);
431 return GST_EVENT_SEQNUM (event);
435 * gst_event_set_seqnum:
436 * @event: A #GstEvent.
437 * @seqnum: A sequence number.
439 * Set the sequence number of a event.
441 * This function might be called by the creator of a event to indicate that the
442 * event relates to other events or messages. See gst_event_get_seqnum() for
448 gst_event_set_seqnum (GstEvent * event, guint32 seqnum)
450 g_return_if_fail (GST_IS_EVENT (event));
451 g_return_if_fail (seqnum != GST_SEQNUM_INVALID);
452 g_return_if_fail (gst_event_is_writable (event));
454 GST_EVENT_SEQNUM (event) = seqnum;
458 * gst_event_get_running_time_offset:
459 * @event: A #GstEvent.
461 * Retrieve the accumulated running time offset of the event.
463 * Events passing through #GstPads that have a running time
464 * offset set via gst_pad_set_offset() will get their offset
465 * adjusted according to the pad's offset.
467 * If the event contains any information that related to the
468 * running time, this information will need to be updated
469 * before usage with this offset.
471 * Returns: The event's running time offset
478 gst_event_get_running_time_offset (GstEvent * event)
480 g_return_val_if_fail (GST_IS_EVENT (event), 0);
482 return ((GstEventImpl *) event)->running_time_offset;
486 * gst_event_set_running_time_offset:
487 * @event: A #GstEvent.
488 * @offset: A the new running time offset
490 * Set the running time offset of a event. See
491 * gst_event_get_running_time_offset() for more information.
498 gst_event_set_running_time_offset (GstEvent * event, gint64 offset)
500 g_return_if_fail (GST_IS_EVENT (event));
501 g_return_if_fail (gst_event_is_writable (event));
503 ((GstEventImpl *) event)->running_time_offset = offset;
507 * gst_event_new_flush_start:
509 * Allocate a new flush start event. The flush start event can be sent
510 * upstream and downstream and travels out-of-bounds with the dataflow.
512 * It marks pads as being flushing and will make them return
513 * #GST_FLOW_FLUSHING when used for data flow with gst_pad_push(),
514 * gst_pad_chain(), gst_pad_get_range() and gst_pad_pull_range().
515 * Any event (except a #GST_EVENT_FLUSH_STOP) received
516 * on a flushing pad will return %FALSE immediately.
518 * Elements should unlock any blocking functions and exit their streaming
519 * functions as fast as possible when this event is received.
521 * This event is typically generated after a seek to flush out all queued data
522 * in the pipeline so that the new media is played as soon as possible.
524 * Returns: (transfer full): a new flush start event.
527 gst_event_new_flush_start (void)
529 return gst_event_new_custom (GST_EVENT_FLUSH_START, NULL);
533 * gst_event_new_flush_stop:
534 * @reset_time: if time should be reset
536 * Allocate a new flush stop event. The flush stop event can be sent
537 * upstream and downstream and travels serialized with the dataflow.
538 * It is typically sent after sending a FLUSH_START event to make the
539 * pads accept data again.
541 * Elements can process this event synchronized with the dataflow since
542 * the preceding FLUSH_START event stopped the dataflow.
544 * This event is typically generated to complete a seek and to resume
547 * Returns: (transfer full): a new flush stop event.
550 gst_event_new_flush_stop (gboolean reset_time)
554 GST_CAT_INFO (GST_CAT_EVENT, "creating flush stop %d", reset_time);
556 event = gst_event_new_custom (GST_EVENT_FLUSH_STOP,
557 gst_structure_new_id (GST_QUARK (EVENT_FLUSH_STOP),
558 GST_QUARK (RESET_TIME), G_TYPE_BOOLEAN, reset_time, NULL));
564 * gst_event_parse_flush_stop:
565 * @event: The event to parse
566 * @reset_time: (out): if time should be reset
568 * Parse the FLUSH_STOP event and retrieve the @reset_time member.
571 gst_event_parse_flush_stop (GstEvent * event, gboolean * reset_time)
573 GstStructure *structure;
575 g_return_if_fail (GST_IS_EVENT (event));
576 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_FLUSH_STOP);
578 structure = GST_EVENT_STRUCTURE (event);
579 if (G_LIKELY (reset_time))
581 g_value_get_boolean (gst_structure_id_get_value (structure,
582 GST_QUARK (RESET_TIME)));
586 * gst_event_new_select_streams:
587 * @streams: (element-type utf8) (transfer none): the list of streams to
590 * Allocate a new select-streams event.
592 * The select-streams event requests the specified @streams to be activated.
594 * The list of @streams corresponds to the "Stream ID" of each stream to be
595 * activated. Those ID can be obtained via the #GstStream objects present
596 * in #GST_EVENT_STREAM_START, #GST_EVENT_STREAM_COLLECTION or
597 * #GST_MESSAGE_STREAM_COLLECTION.
599 * Note: The list of @streams can not be empty.
601 * Returns: (transfer full): a new select-streams event or %NULL in case of
602 * an error (like an empty streams list).
607 gst_event_new_select_streams (GList * streams)
610 GValue val = G_VALUE_INIT;
614 g_return_val_if_fail (streams != NULL, NULL);
616 GST_CAT_INFO (GST_CAT_EVENT, "Creating new select-streams event");
617 struc = gst_structure_new_id_empty (GST_QUARK (EVENT_SELECT_STREAMS));
618 g_value_init (&val, GST_TYPE_LIST);
619 /* Fill struc with streams */
620 for (tmpl = streams; tmpl; tmpl = tmpl->next) {
621 GValue strval = G_VALUE_INIT;
622 const gchar *str = (const gchar *) tmpl->data;
623 g_value_init (&strval, G_TYPE_STRING);
624 g_value_set_string (&strval, str);
625 gst_value_list_append_and_take_value (&val, &strval);
627 gst_structure_id_take_value (struc, GST_QUARK (STREAMS), &val);
628 event = gst_event_new_custom (GST_EVENT_SELECT_STREAMS, struc);
634 * gst_event_parse_select_streams:
635 * @event: The event to parse
636 * @streams: (out) (element-type utf8) (transfer full): the streams
638 * Parse the SELECT_STREAMS event and retrieve the contained streams.
643 gst_event_parse_select_streams (GstEvent * event, GList ** streams)
645 GstStructure *structure;
648 g_return_if_fail (GST_IS_EVENT (event));
649 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SELECT_STREAMS);
651 structure = GST_EVENT_STRUCTURE (event);
652 if (G_LIKELY (streams)) {
653 const GValue *vlist =
654 gst_structure_id_get_value (structure, GST_QUARK (STREAMS));
655 guint i, sz = gst_value_list_get_size (vlist);
656 for (i = 0; i < sz; i++) {
657 const GValue *strv = gst_value_list_get_value (vlist, i);
658 res = g_list_append (res, g_value_dup_string (strv));
666 * gst_event_new_stream_group_done:
667 * @group_id: the group id of the stream group which is ending
669 * Create a new Stream Group Done event. The stream-group-done event can
670 * only travel downstream synchronized with the buffer flow. Elements
671 * that receive the event on a pad should handle it mostly like EOS,
672 * and emit any data or pending buffers that would depend on more data
673 * arriving and unblock, since there won't be any more data.
675 * This event is followed by EOS at some point in the future, and is
676 * generally used when switching pads - to unblock downstream so that
677 * new pads can be exposed before sending EOS on the existing pads.
679 * Returns: (transfer full): the new stream-group-done event.
684 gst_event_new_stream_group_done (guint group_id)
688 s = gst_structure_new_id (GST_QUARK (EVENT_STREAM_GROUP_DONE),
689 GST_QUARK (GROUP_ID), G_TYPE_UINT, group_id, NULL);
691 return gst_event_new_custom (GST_EVENT_STREAM_GROUP_DONE, s);
695 * gst_event_parse_stream_group_done:
696 * @event: a stream-group-done event.
697 * @group_id: (out): address of variable to store the group id into
699 * Parse a stream-group-done @event and store the result in the given
700 * @group_id location.
705 gst_event_parse_stream_group_done (GstEvent * event, guint * group_id)
707 g_return_if_fail (event != NULL);
708 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_GROUP_DONE);
711 gst_structure_id_get (GST_EVENT_STRUCTURE (event),
712 GST_QUARK (GROUP_ID), G_TYPE_UINT, group_id, NULL);
719 * Create a new EOS event. The eos event can only travel downstream
720 * synchronized with the buffer flow. Elements that receive the EOS
721 * event on a pad can return #GST_FLOW_EOS as a #GstFlowReturn
722 * when data after the EOS event arrives.
724 * The EOS event will travel down to the sink elements in the pipeline
725 * which will then post the #GST_MESSAGE_EOS on the bus after they have
726 * finished playing any buffered data.
728 * When all sinks have posted an EOS message, an EOS message is
729 * forwarded to the application.
731 * The EOS event itself will not cause any state transitions of the pipeline.
733 * Returns: (transfer full): the new EOS event.
736 gst_event_new_eos (void)
738 return gst_event_new_custom (GST_EVENT_EOS, NULL);
743 * @timestamp: the start time (pts) of the gap
744 * @duration: the duration of the gap
746 * Create a new GAP event. A gap event can be thought of as conceptually
747 * equivalent to a buffer to signal that there is no data for a certain
748 * amount of time. This is useful to signal a gap to downstream elements
749 * which may wait for data, such as muxers or mixers or overlays, especially
750 * for sparse streams such as subtitle streams.
752 * Returns: (transfer full): the new GAP event.
755 gst_event_new_gap (GstClockTime timestamp, GstClockTime duration)
759 g_return_val_if_fail (GST_CLOCK_TIME_IS_VALID (timestamp), NULL);
761 GST_CAT_TRACE (GST_CAT_EVENT, "creating gap %" GST_TIME_FORMAT " - "
762 "%" GST_TIME_FORMAT " (duration: %" GST_TIME_FORMAT ")",
763 GST_TIME_ARGS (timestamp), GST_TIME_ARGS (timestamp + duration),
764 GST_TIME_ARGS (duration));
766 event = gst_event_new_custom (GST_EVENT_GAP,
767 gst_structure_new_id (GST_QUARK (EVENT_GAP),
768 GST_QUARK (TIMESTAMP), GST_TYPE_CLOCK_TIME, timestamp,
769 GST_QUARK (DURATION), GST_TYPE_CLOCK_TIME, duration, NULL));
775 * gst_event_parse_gap:
776 * @event: a #GstEvent of type #GST_EVENT_GAP
777 * @timestamp: (out) (allow-none): location where to store the
778 * start time (pts) of the gap, or %NULL
779 * @duration: (out) (allow-none): location where to store the duration of
782 * Extract timestamp and duration from a new GAP event.
785 gst_event_parse_gap (GstEvent * event, GstClockTime * timestamp,
786 GstClockTime * duration)
788 GstStructure *structure;
790 g_return_if_fail (GST_IS_EVENT (event));
791 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_GAP);
793 structure = GST_EVENT_STRUCTURE (event);
794 gst_structure_id_get (structure,
795 GST_QUARK (TIMESTAMP), GST_TYPE_CLOCK_TIME, timestamp,
796 GST_QUARK (DURATION), GST_TYPE_CLOCK_TIME, duration, NULL);
800 * gst_event_new_caps:
801 * @caps: (transfer none): a #GstCaps
803 * Create a new CAPS event for @caps. The caps event can only travel downstream
804 * synchronized with the buffer flow and contains the format of the buffers
805 * that will follow after the event.
807 * Returns: (transfer full) (nullable): the new CAPS event.
810 gst_event_new_caps (GstCaps * caps)
814 g_return_val_if_fail (caps != NULL, NULL);
815 g_return_val_if_fail (gst_caps_is_fixed (caps), NULL);
817 GST_CAT_INFO (GST_CAT_EVENT, "creating caps event %" GST_PTR_FORMAT, caps);
819 event = gst_event_new_custom (GST_EVENT_CAPS,
820 gst_structure_new_id (GST_QUARK (EVENT_CAPS),
821 GST_QUARK (CAPS), GST_TYPE_CAPS, caps, NULL));
827 * gst_event_parse_caps:
828 * @event: The event to parse
829 * @caps: (out) (transfer none): A pointer to the caps
831 * Get the caps from @event. The caps remains valid as long as @event remains
835 gst_event_parse_caps (GstEvent * event, GstCaps ** caps)
837 GstStructure *structure;
839 g_return_if_fail (GST_IS_EVENT (event));
840 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_CAPS);
842 structure = GST_EVENT_STRUCTURE (event);
845 g_value_get_boxed (gst_structure_id_get_value (structure,
850 * gst_event_new_segment:
851 * @segment: (transfer none): a #GstSegment
853 * Create a new SEGMENT event for @segment. The segment event can only travel
854 * downstream synchronized with the buffer flow and contains timing information
855 * and playback properties for the buffers that will follow.
857 * The segment event marks the range of buffers to be processed. All
858 * data not within the segment range is not to be processed. This can be
859 * used intelligently by plugins to apply more efficient methods of skipping
860 * unneeded data. The valid range is expressed with the @start and @stop
863 * The time value of the segment is used in conjunction with the start
864 * value to convert the buffer timestamps into the stream time. This is
865 * usually done in sinks to report the current stream_time.
866 * @time represents the stream_time of a buffer carrying a timestamp of
867 * @start. @time cannot be -1.
869 * @start cannot be -1, @stop can be -1. If there
870 * is a valid @stop given, it must be greater or equal the @start, including
871 * when the indicated playback @rate is < 0.
873 * The @applied_rate value provides information about any rate adjustment that
874 * has already been made to the timestamps and content on the buffers of the
875 * stream. (@rate * @applied_rate) should always equal the rate that has been
876 * requested for playback. For example, if an element has an input segment
877 * with intended playback @rate of 2.0 and applied_rate of 1.0, it can adjust
878 * incoming timestamps and buffer content by half and output a segment event
879 * with @rate of 1.0 and @applied_rate of 2.0
881 * After a segment event, the buffer stream time is calculated with:
883 * time + (TIMESTAMP(buf) - start) * ABS (rate * applied_rate)
885 * Returns: (transfer full) (nullable): the new SEGMENT event.
888 gst_event_new_segment (const GstSegment * segment)
892 g_return_val_if_fail (segment != NULL, NULL);
893 g_return_val_if_fail (segment->rate != 0.0, NULL);
894 g_return_val_if_fail (segment->applied_rate != 0.0, NULL);
895 g_return_val_if_fail (segment->format != GST_FORMAT_UNDEFINED, NULL);
897 GST_CAT_INFO (GST_CAT_EVENT, "creating segment event %" GST_SEGMENT_FORMAT,
900 event = gst_event_new_custom (GST_EVENT_SEGMENT,
901 gst_structure_new_id (GST_QUARK (EVENT_SEGMENT),
902 GST_QUARK (SEGMENT), GST_TYPE_SEGMENT, segment, NULL));
908 * gst_event_parse_segment:
909 * @event: The event to parse
910 * @segment: (out) (transfer none): a pointer to a #GstSegment
912 * Parses a segment @event and stores the result in the given @segment location.
913 * @segment remains valid only until the @event is freed. Don't modify the segment
914 * and make a copy if you want to modify it or store it for later use.
917 gst_event_parse_segment (GstEvent * event, const GstSegment ** segment)
919 GstStructure *structure;
921 g_return_if_fail (GST_IS_EVENT (event));
922 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEGMENT);
925 structure = GST_EVENT_STRUCTURE (event);
926 *segment = g_value_get_boxed (gst_structure_id_get_value (structure,
927 GST_QUARK (SEGMENT)));
932 * gst_event_copy_segment:
933 * @event: The event to parse
934 * @segment: a pointer to a #GstSegment
936 * Parses a segment @event and copies the #GstSegment into the location
940 gst_event_copy_segment (GstEvent * event, GstSegment * segment)
942 const GstSegment *src;
944 g_return_if_fail (GST_IS_EVENT (event));
945 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEGMENT);
948 gst_event_parse_segment (event, &src);
949 gst_segment_copy_into (src, segment);
955 * @taglist: (transfer full): metadata list. The event will take ownership
958 * Generates a metadata tag event from the given @taglist.
960 * The scope of the taglist specifies if the taglist applies to the
961 * complete medium or only to this specific stream. As the tag event
962 * is a sticky event, elements should merge tags received from
963 * upstream with a given scope with their own tags with the same
964 * scope and create a new tag event from it.
966 * Returns: (transfer full): a new #GstEvent
969 gst_event_new_tag (GstTagList * taglist)
972 GValue val = G_VALUE_INIT;
973 const gchar *names[] = { "GstTagList-stream", "GstTagList-global" };
975 g_return_val_if_fail (taglist != NULL, NULL);
977 s = gst_structure_new_empty (names[gst_tag_list_get_scope (taglist)]);
978 g_value_init (&val, GST_TYPE_TAG_LIST);
979 g_value_take_boxed (&val, taglist);
980 gst_structure_id_take_value (s, GST_QUARK (TAGLIST), &val);
981 return gst_event_new_custom (GST_EVENT_TAG, s);
985 * gst_event_parse_tag:
986 * @event: a tag event
987 * @taglist: (out) (transfer none): pointer to metadata list
989 * Parses a tag @event and stores the results in the given @taglist location.
990 * No reference to the taglist will be returned, it remains valid only until
991 * the @event is freed. Don't modify or free the taglist, make a copy if you
992 * want to modify it or store it for later use.
995 gst_event_parse_tag (GstEvent * event, GstTagList ** taglist)
999 g_return_if_fail (GST_IS_EVENT (event));
1000 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TAG);
1002 val = gst_structure_id_get_value (GST_EVENT_STRUCTURE (event),
1003 GST_QUARK (TAGLIST));
1006 *taglist = (GstTagList *) g_value_get_boxed (val);
1009 /* buffersize event */
1011 * gst_event_new_buffer_size:
1012 * @format: buffer format
1013 * @minsize: minimum buffer size
1014 * @maxsize: maximum buffer size
1015 * @async: thread behavior
1017 * Create a new buffersize event. The event is sent downstream and notifies
1018 * elements that they should provide a buffer of the specified dimensions.
1020 * When the @async flag is set, a thread boundary is preferred.
1022 * Returns: (transfer full): a new #GstEvent
1025 gst_event_new_buffer_size (GstFormat format, gint64 minsize,
1026 gint64 maxsize, gboolean async)
1029 GstStructure *structure;
1031 GST_CAT_INFO (GST_CAT_EVENT,
1032 "creating buffersize format %s, minsize %" G_GINT64_FORMAT
1033 ", maxsize %" G_GINT64_FORMAT ", async %d", gst_format_get_name (format),
1034 minsize, maxsize, async);
1036 structure = gst_structure_new_id (GST_QUARK (EVENT_BUFFER_SIZE),
1037 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1038 GST_QUARK (MINSIZE), G_TYPE_INT64, minsize,
1039 GST_QUARK (MAXSIZE), G_TYPE_INT64, maxsize,
1040 GST_QUARK (ASYNC), G_TYPE_BOOLEAN, async, NULL);
1041 event = gst_event_new_custom (GST_EVENT_BUFFERSIZE, structure);
1047 * gst_event_parse_buffer_size:
1048 * @event: The event to query
1049 * @format: (out): A pointer to store the format in
1050 * @minsize: (out): A pointer to store the minsize in
1051 * @maxsize: (out): A pointer to store the maxsize in
1052 * @async: (out): A pointer to store the async-flag in
1054 * Get the format, minsize, maxsize and async-flag in the buffersize event.
1057 gst_event_parse_buffer_size (GstEvent * event, GstFormat * format,
1058 gint64 * minsize, gint64 * maxsize, gboolean * async)
1060 const GstStructure *structure;
1062 g_return_if_fail (GST_IS_EVENT (event));
1063 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_BUFFERSIZE);
1065 structure = GST_EVENT_STRUCTURE (event);
1067 *format = (GstFormat)
1068 g_value_get_enum (gst_structure_id_get_value (structure,
1069 GST_QUARK (FORMAT)));
1072 g_value_get_int64 (gst_structure_id_get_value (structure,
1073 GST_QUARK (MINSIZE)));
1076 g_value_get_int64 (gst_structure_id_get_value (structure,
1077 GST_QUARK (MAXSIZE)));
1080 g_value_get_boolean (gst_structure_id_get_value (structure,
1081 GST_QUARK (ASYNC)));
1085 * gst_event_new_qos:
1086 * @type: the QoS type
1087 * @proportion: the proportion of the qos message
1088 * @diff: The time difference of the last Clock sync
1089 * @timestamp: The timestamp of the buffer
1091 * Allocate a new qos event with the given values.
1092 * The QOS event is generated in an element that wants an upstream
1093 * element to either reduce or increase its rate because of
1094 * high/low CPU load or other resource usage such as network performance or
1095 * throttling. Typically sinks generate these events for each buffer
1098 * @type indicates the reason for the QoS event. #GST_QOS_TYPE_OVERFLOW is
1099 * used when a buffer arrived in time or when the sink cannot keep up with
1100 * the upstream datarate. #GST_QOS_TYPE_UNDERFLOW is when the sink is not
1101 * receiving buffers fast enough and thus has to drop late buffers.
1102 * #GST_QOS_TYPE_THROTTLE is used when the datarate is artificially limited
1103 * by the application, for example to reduce power consumption.
1105 * @proportion indicates the real-time performance of the streaming in the
1106 * element that generated the QoS event (usually the sink). The value is
1107 * generally computed based on more long term statistics about the streams
1108 * timestamps compared to the clock.
1109 * A value < 1.0 indicates that the upstream element is producing data faster
1110 * than real-time. A value > 1.0 indicates that the upstream element is not
1111 * producing data fast enough. 1.0 is the ideal @proportion value. The
1112 * proportion value can safely be used to lower or increase the quality of
1115 * @diff is the difference against the clock in running time of the last
1116 * buffer that caused the element to generate the QOS event. A negative value
1117 * means that the buffer with @timestamp arrived in time. A positive value
1118 * indicates how late the buffer with @timestamp was. When throttling is
1119 * enabled, @diff will be set to the requested throttling interval.
1121 * @timestamp is the timestamp of the last buffer that cause the element
1122 * to generate the QOS event. It is expressed in running time and thus an ever
1125 * The upstream element can use the @diff and @timestamp values to decide
1126 * whether to process more buffers. For positive @diff, all buffers with
1127 * timestamp <= @timestamp + @diff will certainly arrive late in the sink
1128 * as well. A (negative) @diff value so that @timestamp + @diff would yield a
1129 * result smaller than 0 is not allowed.
1131 * The application can use general event probes to intercept the QoS
1132 * event and implement custom application specific QoS handling.
1134 * Returns: (transfer full) (nullable): a new QOS event.
1137 gst_event_new_qos (GstQOSType type, gdouble proportion,
1138 GstClockTimeDiff diff, GstClockTime timestamp)
1141 GstStructure *structure;
1143 /* diff must be positive or timestamp + diff must be positive */
1144 g_return_val_if_fail (diff >= 0 || -diff <= timestamp, NULL);
1146 GST_CAT_LOG (GST_CAT_EVENT,
1147 "creating qos type %d, proportion %lf, diff %" G_GINT64_FORMAT
1148 ", timestamp %" GST_TIME_FORMAT, type, proportion,
1149 diff, GST_TIME_ARGS (timestamp));
1151 structure = gst_structure_new_id (GST_QUARK (EVENT_QOS),
1152 GST_QUARK (TYPE), GST_TYPE_QOS_TYPE, type,
1153 GST_QUARK (PROPORTION), G_TYPE_DOUBLE, proportion,
1154 GST_QUARK (DIFF), G_TYPE_INT64, diff,
1155 GST_QUARK (TIMESTAMP), G_TYPE_UINT64, timestamp, NULL);
1156 event = gst_event_new_custom (GST_EVENT_QOS, structure);
1162 * gst_event_parse_qos:
1163 * @event: The event to query
1164 * @type: (out): A pointer to store the QoS type in
1165 * @proportion: (out): A pointer to store the proportion in
1166 * @diff: (out): A pointer to store the diff in
1167 * @timestamp: (out): A pointer to store the timestamp in
1169 * Get the type, proportion, diff and timestamp in the qos event. See
1170 * gst_event_new_qos() for more information about the different QoS values.
1172 * @timestamp will be adjusted for any pad offsets of pads it was passing through.
1175 gst_event_parse_qos (GstEvent * event, GstQOSType * type,
1176 gdouble * proportion, GstClockTimeDiff * diff, GstClockTime * timestamp)
1178 const GstStructure *structure;
1180 g_return_if_fail (GST_IS_EVENT (event));
1181 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_QOS);
1183 structure = GST_EVENT_STRUCTURE (event);
1185 *type = (GstQOSType)
1186 g_value_get_enum (gst_structure_id_get_value (structure,
1190 g_value_get_double (gst_structure_id_get_value (structure,
1191 GST_QUARK (PROPORTION)));
1194 g_value_get_int64 (gst_structure_id_get_value (structure,
1197 gint64 offset = gst_event_get_running_time_offset (event);
1198 GstClockTimeDiff diff_ =
1199 g_value_get_int64 (gst_structure_id_get_value (structure,
1203 g_value_get_uint64 (gst_structure_id_get_value (structure,
1204 GST_QUARK (TIMESTAMP)));
1205 /* Catch underflows */
1206 if (*timestamp > -offset)
1207 *timestamp += offset;
1211 /* Make sure that timestamp + diff is always >= 0. Because
1212 * of the running time offset this might not be true */
1213 if (diff_ < 0 && *timestamp < -diff_)
1214 *timestamp = (GstClockTime) - diff_;
1219 * gst_event_new_seek:
1220 * @rate: The new playback rate
1221 * @format: The format of the seek values
1222 * @flags: The optional seek flags
1223 * @start_type: The type and flags for the new start position
1224 * @start: The value of the new start position
1225 * @stop_type: The type and flags for the new stop position
1226 * @stop: The value of the new stop position
1228 * Allocate a new seek event with the given parameters.
1230 * The seek event configures playback of the pipeline between @start to @stop
1231 * at the speed given in @rate, also called a playback segment.
1232 * The @start and @stop values are expressed in @format.
1234 * A @rate of 1.0 means normal playback rate, 2.0 means double speed.
1235 * Negatives values means backwards playback. A value of 0.0 for the
1236 * rate is not allowed and should be accomplished instead by PAUSING the
1239 * A pipeline has a default playback segment configured with a start
1240 * position of 0, a stop position of -1 and a rate of 1.0. The currently
1241 * configured playback segment can be queried with #GST_QUERY_SEGMENT.
1243 * @start_type and @stop_type specify how to adjust the currently configured
1244 * start and stop fields in playback segment. Adjustments can be made relative
1245 * or absolute to the last configured values. A type of #GST_SEEK_TYPE_NONE
1246 * means that the position should not be updated.
1248 * When the rate is positive and @start has been updated, playback will start
1249 * from the newly configured start position.
1251 * For negative rates, playback will start from the newly configured stop
1252 * position (if any). If the stop position is updated, it must be different from
1253 * -1 (#GST_CLOCK_TIME_NONE) for negative rates.
1255 * It is not possible to seek relative to the current playback position, to do
1256 * this, PAUSE the pipeline, query the current playback position with
1257 * #GST_QUERY_POSITION and update the playback segment current position with a
1258 * #GST_SEEK_TYPE_SET to the desired position.
1260 * Returns: (transfer full) (nullable): a new seek event.
1263 gst_event_new_seek (gdouble rate, GstFormat format, GstSeekFlags flags,
1264 GstSeekType start_type, gint64 start, GstSeekType stop_type, gint64 stop)
1267 GstStructure *structure;
1269 g_return_val_if_fail (rate != 0.0, NULL);
1271 /* SNAP flags only make sense in combination with the KEYUNIT flag. Warn
1272 * and unset the SNAP flags if they're set without the KEYUNIT flag */
1273 if (!(flags & GST_SEEK_FLAG_KEY_UNIT) &&
1274 (flags & (GST_SEEK_FLAG_SNAP_BEFORE | GST_SEEK_FLAG_SNAP_AFTER |
1275 GST_SEEK_FLAG_SNAP_NEAREST))) {
1276 g_warning ("SNAP seeks only work in combination with the KEY_UNIT "
1277 "flag, ignoring SNAP flags");
1279 ~(GST_SEEK_FLAG_SNAP_BEFORE | GST_SEEK_FLAG_SNAP_AFTER |
1280 GST_SEEK_FLAG_SNAP_NEAREST);
1283 if (format == GST_FORMAT_TIME) {
1284 GST_CAT_INFO (GST_CAT_EVENT,
1285 "creating seek rate %lf, format TIME, flags %d, "
1286 "start_type %d, start %" GST_TIME_FORMAT ", "
1287 "stop_type %d, stop %" GST_TIME_FORMAT,
1288 rate, flags, start_type, GST_TIME_ARGS (start),
1289 stop_type, GST_TIME_ARGS (stop));
1291 GST_CAT_INFO (GST_CAT_EVENT,
1292 "creating seek rate %lf, format %s, flags %d, "
1293 "start_type %d, start %" G_GINT64_FORMAT ", "
1294 "stop_type %d, stop %" G_GINT64_FORMAT,
1295 rate, gst_format_get_name (format), flags, start_type, start, stop_type,
1299 structure = gst_structure_new_id (GST_QUARK (EVENT_SEEK),
1300 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
1301 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1302 GST_QUARK (FLAGS), GST_TYPE_SEEK_FLAGS, flags,
1303 GST_QUARK (CUR_TYPE), GST_TYPE_SEEK_TYPE, start_type,
1304 GST_QUARK (CUR), G_TYPE_INT64, start,
1305 GST_QUARK (STOP_TYPE), GST_TYPE_SEEK_TYPE, stop_type,
1306 GST_QUARK (STOP), G_TYPE_INT64, stop, NULL);
1307 event = gst_event_new_custom (GST_EVENT_SEEK, structure);
1313 * gst_event_parse_seek:
1314 * @event: a seek event
1315 * @rate: (out): result location for the rate
1316 * @format: (out): result location for the stream format
1317 * @flags: (out): result location for the #GstSeekFlags
1318 * @start_type: (out): result location for the #GstSeekType of the start position
1319 * @start: (out): result location for the start position expressed in @format
1320 * @stop_type: (out): result location for the #GstSeekType of the stop position
1321 * @stop: (out): result location for the stop position expressed in @format
1323 * Parses a seek @event and stores the results in the given result locations.
1326 gst_event_parse_seek (GstEvent * event, gdouble * rate,
1327 GstFormat * format, GstSeekFlags * flags, GstSeekType * start_type,
1328 gint64 * start, GstSeekType * stop_type, gint64 * stop)
1330 const GstStructure *structure;
1332 g_return_if_fail (GST_IS_EVENT (event));
1333 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEEK);
1335 structure = GST_EVENT_STRUCTURE (event);
1338 g_value_get_double (gst_structure_id_get_value (structure,
1341 *format = (GstFormat)
1342 g_value_get_enum (gst_structure_id_get_value (structure,
1343 GST_QUARK (FORMAT)));
1345 *flags = (GstSeekFlags)
1346 g_value_get_flags (gst_structure_id_get_value (structure,
1347 GST_QUARK (FLAGS)));
1349 *start_type = (GstSeekType)
1350 g_value_get_enum (gst_structure_id_get_value (structure,
1351 GST_QUARK (CUR_TYPE)));
1354 g_value_get_int64 (gst_structure_id_get_value (structure,
1357 *stop_type = (GstSeekType)
1358 g_value_get_enum (gst_structure_id_get_value (structure,
1359 GST_QUARK (STOP_TYPE)));
1362 g_value_get_int64 (gst_structure_id_get_value (structure,
1367 * gst_event_new_navigation:
1368 * @structure: (transfer full): description of the event. The event will take
1369 * ownership of the structure.
1371 * Create a new navigation event from the given description.
1373 * Returns: (transfer full): a new #GstEvent
1376 gst_event_new_navigation (GstStructure * structure)
1378 g_return_val_if_fail (structure != NULL, NULL);
1380 return gst_event_new_custom (GST_EVENT_NAVIGATION, structure);
1384 * gst_event_new_latency:
1385 * @latency: the new latency value
1387 * Create a new latency event. The event is sent upstream from the sinks and
1388 * notifies elements that they should add an additional @latency to the
1389 * running time before synchronising against the clock.
1391 * The latency is mostly used in live sinks and is always expressed in
1394 * Returns: (transfer full): a new #GstEvent
1397 gst_event_new_latency (GstClockTime latency)
1400 GstStructure *structure;
1402 GST_CAT_INFO (GST_CAT_EVENT,
1403 "creating latency event %" GST_TIME_FORMAT, GST_TIME_ARGS (latency));
1405 structure = gst_structure_new_id (GST_QUARK (EVENT_LATENCY),
1406 GST_QUARK (LATENCY), G_TYPE_UINT64, latency, NULL);
1407 event = gst_event_new_custom (GST_EVENT_LATENCY, structure);
1413 * gst_event_parse_latency:
1414 * @event: The event to query
1415 * @latency: (out): A pointer to store the latency in.
1417 * Get the latency in the latency event.
1420 gst_event_parse_latency (GstEvent * event, GstClockTime * latency)
1422 g_return_if_fail (GST_IS_EVENT (event));
1423 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_LATENCY);
1427 g_value_get_uint64 (gst_structure_id_get_value (GST_EVENT_STRUCTURE
1428 (event), GST_QUARK (LATENCY)));
1432 * gst_event_new_step:
1433 * @format: the format of @amount
1434 * @amount: the amount of data to step
1435 * @rate: the step rate
1436 * @flush: flushing steps
1437 * @intermediate: intermediate steps
1439 * Create a new step event. The purpose of the step event is to instruct a sink
1440 * to skip @amount (expressed in @format) of media. It can be used to implement
1441 * stepping through the video frame by frame or for doing fast trick modes.
1443 * A rate of <= 0.0 is not allowed. Pause the pipeline, for the effect of rate
1444 * = 0.0 or first reverse the direction of playback using a seek event to get
1445 * the same effect as rate < 0.0.
1447 * The @flush flag will clear any pending data in the pipeline before starting
1448 * the step operation.
1450 * The @intermediate flag instructs the pipeline that this step operation is
1451 * part of a larger step operation.
1453 * Returns: (transfer full) (nullable): a new #GstEvent
1456 gst_event_new_step (GstFormat format, guint64 amount, gdouble rate,
1457 gboolean flush, gboolean intermediate)
1460 GstStructure *structure;
1462 g_return_val_if_fail (rate > 0.0, NULL);
1464 GST_CAT_INFO (GST_CAT_EVENT, "creating step event");
1466 structure = gst_structure_new_id (GST_QUARK (EVENT_STEP),
1467 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
1468 GST_QUARK (AMOUNT), G_TYPE_UINT64, amount,
1469 GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
1470 GST_QUARK (FLUSH), G_TYPE_BOOLEAN, flush,
1471 GST_QUARK (INTERMEDIATE), G_TYPE_BOOLEAN, intermediate, NULL);
1472 event = gst_event_new_custom (GST_EVENT_STEP, structure);
1478 * gst_event_parse_step:
1479 * @event: The event to query
1480 * @format: (out) (allow-none): a pointer to store the format in
1481 * @amount: (out) (allow-none): a pointer to store the amount in
1482 * @rate: (out) (allow-none): a pointer to store the rate in
1483 * @flush: (out) (allow-none): a pointer to store the flush boolean in
1484 * @intermediate: (out) (allow-none): a pointer to store the intermediate
1487 * Parse the step event.
1490 gst_event_parse_step (GstEvent * event, GstFormat * format, guint64 * amount,
1491 gdouble * rate, gboolean * flush, gboolean * intermediate)
1493 const GstStructure *structure;
1495 g_return_if_fail (GST_IS_EVENT (event));
1496 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STEP);
1498 structure = GST_EVENT_STRUCTURE (event);
1501 (GstFormat) g_value_get_enum (gst_structure_id_get_value (structure,
1502 GST_QUARK (FORMAT)));
1504 *amount = g_value_get_uint64 (gst_structure_id_get_value (structure,
1505 GST_QUARK (AMOUNT)));
1507 *rate = g_value_get_double (gst_structure_id_get_value (structure,
1510 *flush = g_value_get_boolean (gst_structure_id_get_value (structure,
1511 GST_QUARK (FLUSH)));
1513 *intermediate = g_value_get_boolean (gst_structure_id_get_value (structure,
1514 GST_QUARK (INTERMEDIATE)));
1518 * gst_event_new_reconfigure:
1520 * Create a new reconfigure event. The purpose of the reconfigure event is
1521 * to travel upstream and make elements renegotiate their caps or reconfigure
1522 * their buffer pools. This is useful when changing properties on elements
1523 * or changing the topology of the pipeline.
1525 * Returns: (transfer full): a new #GstEvent
1528 gst_event_new_reconfigure (void)
1532 GST_CAT_INFO (GST_CAT_EVENT, "creating reconfigure event");
1534 event = gst_event_new_custom (GST_EVENT_RECONFIGURE, NULL);
1540 * gst_event_new_sink_message:
1541 * @name: a name for the event
1542 * @msg: (transfer none): the #GstMessage to be posted
1544 * Create a new sink-message event. The purpose of the sink-message event is
1545 * to instruct a sink to post the message contained in the event synchronized
1548 * @name is used to store multiple sticky events on one pad.
1550 * Returns: (transfer full): a new #GstEvent
1552 /* FIXME 2.0: take ownership of msg for consistency? */
1554 gst_event_new_sink_message (const gchar * name, GstMessage * msg)
1557 GstStructure *structure;
1559 g_return_val_if_fail (msg != NULL, NULL);
1561 GST_CAT_INFO (GST_CAT_EVENT, "creating sink-message event");
1563 structure = gst_structure_new_id (g_quark_from_string (name),
1564 GST_QUARK (MESSAGE), GST_TYPE_MESSAGE, msg, NULL);
1565 event = gst_event_new_custom (GST_EVENT_SINK_MESSAGE, structure);
1571 * gst_event_parse_sink_message:
1572 * @event: The event to query
1573 * @msg: (out) (transfer full): a pointer to store the #GstMessage in.
1575 * Parse the sink-message event. Unref @msg after usage.
1578 gst_event_parse_sink_message (GstEvent * event, GstMessage ** msg)
1580 const GstStructure *structure;
1582 g_return_if_fail (GST_IS_EVENT (event));
1583 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SINK_MESSAGE);
1585 structure = GST_EVENT_STRUCTURE (event);
1588 GST_MESSAGE (g_value_dup_boxed (gst_structure_id_get_value
1589 (structure, GST_QUARK (MESSAGE))));
1593 * gst_event_new_stream_start:
1594 * @stream_id: Identifier for this stream
1596 * Create a new STREAM_START event. The stream start event can only
1597 * travel downstream synchronized with the buffer flow. It is expected
1598 * to be the first event that is sent for a new stream.
1600 * Source elements, demuxers and other elements that create new streams
1601 * are supposed to send this event as the first event of a new stream. It
1602 * should not be sent after a flushing seek or in similar situations
1603 * and is used to mark the beginning of a new logical stream. Elements
1604 * combining multiple streams must ensure that this event is only forwarded
1605 * downstream once and not for every single input stream.
1607 * The @stream_id should be a unique string that consists of the upstream
1608 * stream-id, / as separator and a unique stream-id for this specific
1609 * stream. A new stream-id should only be created for a stream if the upstream
1610 * stream is split into (potentially) multiple new streams, e.g. in a demuxer,
1611 * but not for every single element in the pipeline.
1612 * gst_pad_create_stream_id() or gst_pad_create_stream_id_printf() can be
1613 * used to create a stream-id. There are no particular semantics for the
1614 * stream-id, though it should be deterministic (to support stream matching)
1615 * and it might be used to order streams (besides any information conveyed by
1618 * Returns: (transfer full): the new STREAM_START event.
1621 gst_event_new_stream_start (const gchar * stream_id)
1625 g_return_val_if_fail (stream_id != NULL, NULL);
1627 s = gst_structure_new_id (GST_QUARK (EVENT_STREAM_START),
1628 GST_QUARK (STREAM_ID), G_TYPE_STRING, stream_id,
1629 GST_QUARK (FLAGS), GST_TYPE_STREAM_FLAGS, GST_STREAM_FLAG_NONE, NULL);
1631 return gst_event_new_custom (GST_EVENT_STREAM_START, s);
1635 * gst_event_parse_stream_start:
1636 * @event: a stream-start event.
1637 * @stream_id: (out) (transfer none): pointer to store the stream-id
1639 * Parse a stream-id @event and store the result in the given @stream_id
1640 * location. The string stored in @stream_id must not be modified and will
1641 * remain valid only until @event gets freed. Make a copy if you want to
1642 * modify it or store it for later use.
1645 gst_event_parse_stream_start (GstEvent * event, const gchar ** stream_id)
1647 const GstStructure *structure;
1650 g_return_if_fail (event != NULL);
1651 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1653 structure = gst_event_get_structure (event);
1654 val = gst_structure_id_get_value (structure, GST_QUARK (STREAM_ID));
1657 *stream_id = g_value_get_string (val);
1661 * gst_event_set_stream:
1662 * @event: a stream-start event
1663 * @stream: (transfer none): the stream object to set
1665 * Set the @stream on the stream-start @event
1670 gst_event_set_stream (GstEvent * event, GstStream * stream)
1672 g_return_if_fail (event != NULL);
1673 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1674 g_return_if_fail (gst_event_is_writable (event));
1676 gst_structure_id_set (GST_EVENT_STRUCTURE (event),
1677 GST_QUARK (STREAM), GST_TYPE_STREAM, stream, NULL);
1681 * gst_event_parse_stream:
1682 * @event: a stream-start event
1683 * @stream: (out) (transfer full): address of variable to store the stream
1685 * Parse a stream-start @event and extract the #GstStream from it.
1690 gst_event_parse_stream (GstEvent * event, GstStream ** stream)
1692 g_return_if_fail (event != NULL);
1693 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1696 gst_structure_id_get (GST_EVENT_STRUCTURE (event),
1697 GST_QUARK (STREAM), GST_TYPE_STREAM, stream, NULL);
1703 * gst_event_set_stream_flags:
1704 * @event: a stream-start event
1705 * @flags: the stream flags to set
1710 gst_event_set_stream_flags (GstEvent * event, GstStreamFlags flags)
1712 g_return_if_fail (event != NULL);
1713 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1714 g_return_if_fail (gst_event_is_writable (event));
1716 gst_structure_id_set (GST_EVENT_STRUCTURE (event),
1717 GST_QUARK (FLAGS), GST_TYPE_STREAM_FLAGS, flags, NULL);
1721 * gst_event_parse_stream_flags:
1722 * @event: a stream-start event
1723 * @flags: (out): address of variable where to store the stream flags
1728 gst_event_parse_stream_flags (GstEvent * event, GstStreamFlags * flags)
1730 g_return_if_fail (event != NULL);
1731 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1734 gst_structure_id_get (GST_EVENT_STRUCTURE (event),
1735 GST_QUARK (FLAGS), GST_TYPE_STREAM_FLAGS, flags, NULL);
1740 * gst_event_set_group_id:
1741 * @event: a stream-start event
1742 * @group_id: the group id to set
1744 * All streams that have the same group id are supposed to be played
1745 * together, i.e. all streams inside a container file should have the
1746 * same group id but different stream ids. The group id should change
1747 * each time the stream is started, resulting in different group ids
1748 * each time a file is played for example.
1750 * Use gst_util_group_id_next() to get a new group id.
1755 gst_event_set_group_id (GstEvent * event, guint group_id)
1757 g_return_if_fail (event != NULL);
1758 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
1759 g_return_if_fail (gst_event_is_writable (event));
1761 gst_structure_id_set (GST_EVENT_STRUCTURE (event),
1762 GST_QUARK (GROUP_ID), G_TYPE_UINT, group_id, NULL);
1766 * gst_event_parse_group_id:
1767 * @event: a stream-start event
1768 * @group_id: (out): address of variable where to store the group id
1770 * Returns: %TRUE if a group id was set on the event and could be parsed,
1776 gst_event_parse_group_id (GstEvent * event, guint * group_id)
1778 g_return_val_if_fail (event != NULL, FALSE);
1779 g_return_val_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START,
1783 return gst_structure_id_get (GST_EVENT_STRUCTURE (event),
1784 GST_QUARK (GROUP_ID), G_TYPE_UINT, group_id, NULL);
1791 * gst_event_new_stream_collection:
1792 * @collection: Active collection for this data flow
1794 * Create a new STREAM_COLLECTION event. The stream collection event can only
1795 * travel downstream synchronized with the buffer flow.
1797 * Source elements, demuxers and other elements that manage collections
1798 * of streams and post #GstStreamCollection messages on the bus also send
1799 * this event downstream on each pad involved in the collection, so that
1800 * activation of a new collection can be tracked through the downstream
1803 * Returns: (transfer full): the new STREAM_COLLECTION event.
1808 gst_event_new_stream_collection (GstStreamCollection * collection)
1812 g_return_val_if_fail (collection != NULL, NULL);
1813 g_return_val_if_fail (GST_IS_STREAM_COLLECTION (collection), NULL);
1815 s = gst_structure_new_id (GST_QUARK (EVENT_STREAM_COLLECTION),
1816 GST_QUARK (COLLECTION), GST_TYPE_STREAM_COLLECTION, collection, NULL);
1818 return gst_event_new_custom (GST_EVENT_STREAM_COLLECTION, s);
1822 * gst_event_parse_stream_collection:
1823 * @event: a stream-collection event
1824 * @collection: (out): pointer to store the collection
1826 * Retrieve new #GstStreamCollection from STREAM_COLLECTION event @event.
1831 gst_event_parse_stream_collection (GstEvent * event,
1832 GstStreamCollection ** collection)
1834 const GstStructure *structure;
1836 g_return_if_fail (event != NULL);
1837 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_COLLECTION);
1839 structure = gst_event_get_structure (event);
1842 gst_structure_id_get (structure,
1843 GST_QUARK (COLLECTION), GST_TYPE_STREAM_COLLECTION, collection, NULL);
1848 * gst_event_new_toc:
1849 * @toc: (transfer none): #GstToc structure.
1850 * @updated: whether @toc was updated or not.
1852 * Generate a TOC event from the given @toc. The purpose of the TOC event is to
1853 * inform elements that some kind of the TOC was found.
1855 * Returns: (transfer full): a new #GstEvent.
1858 gst_event_new_toc (GstToc * toc, gboolean updated)
1860 GstStructure *toc_struct;
1863 g_return_val_if_fail (toc != NULL, NULL);
1865 GST_CAT_INFO (GST_CAT_EVENT, "creating toc event");
1867 /* need different structure names so sticky_multi event stuff on pads
1868 * works, i.e. both TOC events are kept around */
1869 if (gst_toc_get_scope (toc) == GST_TOC_SCOPE_GLOBAL)
1870 id = GST_QUARK (EVENT_TOC_GLOBAL);
1872 id = GST_QUARK (EVENT_TOC_CURRENT);
1874 toc_struct = gst_structure_new_id (id,
1875 GST_QUARK (TOC), GST_TYPE_TOC, toc,
1876 GST_QUARK (UPDATED), G_TYPE_BOOLEAN, updated, NULL);
1878 return gst_event_new_custom (GST_EVENT_TOC, toc_struct);
1882 * gst_event_parse_toc:
1883 * @event: a TOC event.
1884 * @toc: (out) (transfer full): pointer to #GstToc structure.
1885 * @updated: (out): pointer to store TOC updated flag.
1887 * Parse a TOC @event and store the results in the given @toc and @updated locations.
1890 gst_event_parse_toc (GstEvent * event, GstToc ** toc, gboolean * updated)
1892 const GstStructure *structure;
1894 g_return_if_fail (event != NULL);
1895 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TOC);
1896 g_return_if_fail (toc != NULL);
1898 structure = gst_event_get_structure (event);
1900 gst_structure_id_get (structure,
1901 GST_QUARK (TOC), GST_TYPE_TOC, toc,
1902 GST_QUARK (UPDATED), G_TYPE_BOOLEAN, updated, NULL);
1906 * gst_event_new_toc_select:
1907 * @uid: UID in the TOC to start playback from.
1909 * Generate a TOC select event with the given @uid. The purpose of the
1910 * TOC select event is to start playback based on the TOC's entry with the
1913 * Returns: a new #GstEvent.
1916 gst_event_new_toc_select (const gchar * uid)
1918 GstStructure *structure;
1920 g_return_val_if_fail (uid != NULL, NULL);
1922 GST_CAT_INFO (GST_CAT_EVENT, "creating toc select event for UID: %s", uid);
1924 structure = gst_structure_new_id (GST_QUARK (EVENT_TOC_SELECT),
1925 GST_QUARK (UID), G_TYPE_STRING, uid, NULL);
1927 return gst_event_new_custom (GST_EVENT_TOC_SELECT, structure);
1931 * gst_event_parse_toc_select:
1932 * @event: a TOC select event.
1933 * @uid: (out) (transfer full) (allow-none): storage for the selection UID.
1935 * Parse a TOC select @event and store the results in the given @uid location.
1938 gst_event_parse_toc_select (GstEvent * event, gchar ** uid)
1940 const GstStructure *structure;
1943 g_return_if_fail (event != NULL);
1944 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TOC_SELECT);
1946 structure = gst_event_get_structure (event);
1947 val = gst_structure_id_get_value (structure, GST_QUARK (UID));
1950 *uid = g_strdup (g_value_get_string (val));
1955 * gst_event_new_protection:
1956 * @system_id: (transfer none): a string holding a UUID that uniquely
1957 * identifies a protection system.
1958 * @data: (transfer none): a #GstBuffer holding protection system specific
1959 * information. The reference count of the buffer will be incremented by one.
1960 * @origin: a string indicating where the protection
1961 * information carried in the event was extracted from. The allowed values
1962 * of this string will depend upon the protection scheme.
1964 * Creates a new event containing information specific to a particular
1965 * protection system (uniquely identified by @system_id), by which that
1966 * protection system can acquire key(s) to decrypt a protected stream.
1968 * In order for a decryption element to decrypt media
1969 * protected using a specific system, it first needs all the
1970 * protection system specific information necessary to acquire the decryption
1971 * key(s) for that stream. The functions defined here enable this information
1972 * to be passed in events from elements that extract it
1973 * (e.g., ISOBMFF demuxers, MPEG DASH demuxers) to protection decrypter
1974 * elements that use it.
1976 * Events containing protection system specific information are created using
1977 * #gst_event_new_protection, and they can be parsed by downstream elements
1978 * using #gst_event_parse_protection.
1980 * In Common Encryption, protection system specific information may be located
1981 * within ISOBMFF files, both in movie (moov) boxes and movie fragment (moof)
1982 * boxes; it may also be contained in ContentProtection elements within MPEG
1983 * DASH MPDs. The events created by #gst_event_new_protection contain data
1984 * identifying from which of these locations the encapsulated protection system
1985 * specific information originated. This origin information is required as
1986 * some protection systems use different encodings depending upon where the
1987 * information originates.
1989 * The events returned by gst_event_new_protection() are implemented
1990 * in such a way as to ensure that the most recently-pushed protection info
1991 * event of a particular @origin and @system_id will
1992 * be stuck to the output pad of the sending element.
1994 * Returns: a #GST_EVENT_PROTECTION event, if successful; %NULL
2000 gst_event_new_protection (const gchar * system_id,
2001 GstBuffer * data, const gchar * origin)
2007 g_return_val_if_fail (system_id != NULL, NULL);
2008 g_return_val_if_fail (data != NULL, NULL);
2011 g_strconcat ("GstProtectionEvent", origin ? "-" : "",
2012 origin ? origin : "", "-", system_id, NULL);
2014 GST_CAT_INFO (GST_CAT_EVENT, "creating protection event %s", event_name);
2016 s = gst_structure_new (event_name, "data", GST_TYPE_BUFFER, data,
2017 "system_id", G_TYPE_STRING, system_id, NULL);
2019 gst_structure_set (s, "origin", G_TYPE_STRING, origin, NULL);
2020 event = gst_event_new_custom (GST_EVENT_PROTECTION, s);
2022 g_free (event_name);
2027 * gst_event_parse_protection:
2028 * @event: a #GST_EVENT_PROTECTION event.
2029 * @system_id: (out) (allow-none) (transfer none): pointer to store the UUID
2030 * string uniquely identifying a content protection system.
2031 * @data: (out) (allow-none) (transfer none): pointer to store a #GstBuffer
2032 * holding protection system specific information.
2033 * @origin: (out) (allow-none) (transfer none): pointer to store a value that
2034 * indicates where the protection information carried by @event was extracted
2037 * Parses an event containing protection system specific information and stores
2038 * the results in @system_id, @data and @origin. The data stored in @system_id,
2039 * @origin and @data are valid until @event is released.
2044 gst_event_parse_protection (GstEvent * event, const gchar ** system_id,
2045 GstBuffer ** data, const gchar ** origin)
2047 const GstStructure *s;
2049 g_return_if_fail (event != NULL);
2050 g_return_if_fail (GST_IS_EVENT (event));
2051 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_PROTECTION);
2053 s = gst_event_get_structure (event);
2056 *origin = gst_structure_get_string (s, "origin");
2059 *system_id = gst_structure_get_string (s, "system_id");
2062 const GValue *value = gst_structure_get_value (s, "data");
2063 *data = gst_value_get_buffer (value);
2068 * gst_event_new_segment_done:
2069 * @format: The format of the position being done
2070 * @position: The position of the segment being done
2072 * Create a new segment-done event. This event is sent by elements that
2073 * finish playback of a segment as a result of a segment seek.
2075 * Returns: (transfer full): a new #GstEvent
2078 gst_event_new_segment_done (GstFormat format, gint64 position)
2081 GstStructure *structure;
2083 GST_CAT_INFO (GST_CAT_EVENT, "creating segment-done event");
2085 structure = gst_structure_new_id (GST_QUARK (EVENT_SEGMENT_DONE),
2086 GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
2087 GST_QUARK (POSITION), G_TYPE_INT64, position, NULL);
2089 event = gst_event_new_custom (GST_EVENT_SEGMENT_DONE, structure);
2095 * gst_event_parse_segment_done:
2096 * @event: A valid #GstEvent of type GST_EVENT_SEGMENT_DONE.
2097 * @format: (out) (allow-none): Result location for the format, or %NULL
2098 * @position: (out) (allow-none): Result location for the position, or %NULL
2100 * Extracts the position and format from the segment done message.
2104 gst_event_parse_segment_done (GstEvent * event, GstFormat * format,
2107 const GstStructure *structure;
2110 g_return_if_fail (event != NULL);
2111 g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEGMENT_DONE);
2113 structure = gst_event_get_structure (event);
2115 val = gst_structure_id_get_value (structure, GST_QUARK (FORMAT));
2117 *format = g_value_get_enum (val);
2119 val = gst_structure_id_get_value (structure, GST_QUARK (POSITION));
2120 if (position != NULL)
2121 *position = g_value_get_int64 (val);